1. Field of the Invention
The present invention relates to a protocol for self-addressing control units, and more particularly to a modular sign comprising a plurality of self-addressing control units positioned side by side to form an array, each of the control units having a mechanical sign mechanism for displaying one of a plurality of characters to display a message on the array, which sign can be controlled from a remote location to change the characters displayed by the control units to create and change messages on the sign. Additionally, the present invention relates to the use of a protocol for self-addressing control units for application in any field wherein a plurality of control units are used in a system. Additionally, the present invention relates to a method and apparatus for installing a plurality of control units to form an array.
2. Related Art
In the past signs have been made to have a single image thereon for the life of the sign. Of course, the entire face of the sign could be replaced with a new face. Additionally, it is known to provide signs that can be backlit and have, on the face thereof, slots for holding individual clear panels with characters thereon so that such characters can be arranged to form words. This type of sign is used on movie theater marquees to display the names of the movies playing at the theater, and the times that would such movies are scheduled to begin. However, this type of sign is difficult to install. Additionally, in order to change the names on the sign, one needs to either lower the sign down to ground level or use a ladder to climb up to the sign and remove the panels from the sign and put on new panels bearing the proper characters to spell the proper word to indicate the name of a new movie. Besides being dangerous, this procedure is time intensive. Additionally, this process must be performed frequently, such as on a weekly basis, which compounds the amount of time involved. There is additional time involved in replacing fluorescent bulbs which provide the back lighting for the sign as they burn out.
A prior attempt at overcoming these problems is found in Lesko, et al., U.S. Pat. No. 5,061,921 disclosed a remote-controlled message sign which is controlled by a pager which receives radio signals from a paging service and provides output signals in response to the radio signals. The output signals of the pager are used to control one or more drive motors which move a multiple position message device to a desired position. The display device includes a wheel or drum having an outer cylindrical surface and an axle and is rotatably mounted on the sign. A motor drive rotates the wheel to position the desired letter or number in the window of the sign. A position data reader on the drum determines the position of the drum relative to the window of the sign. However, this does not overcome all of the problems in the prior art.
Another attempt at providing an automatically changeable display sign is disclosed in Daugherty, et al., U.S. Pat. No. 5,184,116 for a back-lightable diffusive sign for displaying alphanumeric characters and graphics comprising a plurality of mechanically moveable elements, each have a dark translucent face and a bright translucent face which are moveable from one to the other face interchangeably by a series of electromechanical driving elements. However, this sign does not overcome all the problems associated with the signs of the prior art.
Accordingly, what is desired, but has not heretofore been achieved, is a sign for displaying messages which messages can be inexpensively and easily changed from a remote location.
Additionally, it has been known is the past to provide a series of control units, such as computers, computer networks, or other controllers, for performing a desired function. In the past, efforts at coordinating the outputs of the various control units involved wiring each separate control unit directly to a main controller to form an electrical and mechanical link. Such a method however, is expensive based on the wiring involved. Another method of linking the control units together is by means of multiplexing which involves an array of many “X” and “Y” connecting wires from the main controller to each of the control units. Further, it is known to serially or sequentially link a main controller to control units by having the installer set switches on each of the control units. Indeed, many of the networking cards currently in use in computer networks are configured by the manufacturer to have a certain switch sequence for identification purposes, and these control units are mixed and matched, but the problem sometimes arises that more than one control unit has the same identification number and causes confusion in the network. All of these methods are material intensive in terms of wires and/or labor intensive and/or require expert installers to understand and install each system and/or are limited by the manufacturer of the units.
Accordingly, what is desired, and has not heretofore been invented is a control unit capable of using one single data path (one wire or parallel wires or fiber optic or radio path) where all of the units are addressed sequentially and set their own addresses based on the referencing of the prior unit to self-address and to self-install without the aid of a technician.
Additionally, in the past there has been a problem with hanging signs and running electricity thereinto. Signs had to be separately, mechanically, installed and separately, electrically, interconnected. For modular signs there has been a problem installing a plurality of units need at an even and aligned position. It is difficult to achieve such alignment because of the measuring that must take place to insure that units are mounted at a aligned height with proper spacing therebetween.
Accordingly, what is needed, and has not heretofore been available, is a method for mounting and electrically connecting a plurality of units which compensates for improper installation.